The extremist group Boko Haram has released 82 school girls who have been captive for more than three years, Nigerian officials said on Saturday.

The girls were released after negotiations, according to reports, and the Nigerian government has released prisoners in return.

Though most reports say the number and other details of the prisoners were not disclosed, The Guardian has reported that five commanders were released.

The 82 women who were released were among more than 270 girls who were abducted at a school in Chibok, located in the northeastern part of Nigeria, in April of 2014. Since the abduction, some girls have escaped, and dozens have been released after negotiations. An estimated 100 are still captive.

“The President directed the security agencies to continue in earnest until all the Chibok girls have been released and reunited with their families,” the Nigerian President Muhammadu Buhari’s office said.

“I am very, very excited with this development,” Yana Galang, whose daughter was among the 276 who were kidnapped, told CNN.

“I hope and pray that my daughter is among these released girls,” Galang added.

The abduction of these school girls received much international public attention, as it sparked the social media campaign #BringBackOurGirls. However, Boko Haram, which has pledged allegiance to the Islamic State, is known to have abducted thousands others over the last eight years.

Buhari’s spokesman said Buhari was thankful to “security agencies, the military, the Government of Switzerland, the International Committee of the Red Cross, and local and international NGOs” for their roles in securing the rescue of the 82 girls.

Boko Haram has existed as a militant group since the late 1990s. The Nigerian government estimates that its violent activities have caused tens of thousands to be killed, and hundreds of thousands to be displaced from their homes.